The present invention relates to substituted phenylcyclohexanecarboxamides having adenosine-uptake-inhibiting action, to processes for their preparation and to their use in medicaments, in particular for treating ischaemic brain disorders.
Adenosine is an endogenic effector with cell-protective activity, in particular under cell-damaging conditions with limited oxygen and substrate supply, such as, for example, in ischaemia, stroke and brain trauma. The neuroprotective action of adenosine is essentially effected via suppression of presynaptic glutamate release and limitation of postsynaptic depolarization. This prevents toxic calcium influx into postsynaptic nerve cells via NMDA receptors. Under ischaemic or hypoxic conditions, the extracellular concentration of adenosine in the CNS is dramatically increased.
There are various indications of a neuroprotective, anticonvulsive, analgesic and sleep-inducing potential of adenosine-uptake inhibitors, since they enhance the intrinsic effects of adenosine by inhibiting its cellular reuptake. Accordingly, adenosine-uptake inhibitors can be administered orally or intravenously for the prevention and treatment of cerebral ischaemia, stroke, reperfusion damage, brain trauma, oedema, spasms, epilepsy, respiratory arrest, cardiac arrest, Reye""s syndrome, cerebral thrombosis, emboli, tumours, haemorrhages, encephalomyelitis, hydroencephalitis, spinal injuries, post-operative brain damage, injuries to the retina or the optical nerve after glaucoma, ischaemia, hypoxia, oedema or trauma and in the treatment of schizophrenia, sleep disturbances and pain (Cerebrovasc. Brain Metab. Rev. 1992, 4, 364-369; Drug Dev. Res. 1993, 28, 410-415; Science 1997, 276, 1265-1268; xe2x80x98Adenosine in the Nervous Systemxe2x80x99, Ed.: Trevor Stone, Academic Press Ltd. 1991, 217-227; Ann. Rep. Med. Chem. 1998, 33. 111-120).
Adenosine-uptake inhibitors can also be employed for potentiating the effect of nucleobase, nucleoside or nucleotide antimetabolites in the chemotherapeutical treatment of cancer and antiviral (for example HIV) chemotherapy (Curr. Med. Chem. 1997, 4, 35-66).
EP-A0 611 767 and EP-A-0 725 064 disclose phenylcyclohexylcarboxamides which can be used for treating atherosclerosis and/or restenosis.
The present invention relates to compounds of the general formula (I) 
in wherein
A, D, E and G are identical or different and represent CH groups or nitrogen atoms,
L1 and L2 are identical or different and independently of one another each represents one or more radicals selected from the group consisting of hydrogen, halogen, hydroxyl, carboxyl, cyano, nitro, trifluoromethyl, trifluoromethoxy, (C1-C6)-alkyl, (C1-C6)-alkoxy or (C1-C6)-alkoxy-carbonyl,
R1 represents the CH2xe2x80x94OH group, or
represents a radical of the formula COxe2x80x94NR4R5 
in which
R4 and R5 are identical or different and each represents hydrogen or (C1-C6)-alkyl,
R2 represents (C3-C8)-cycloalkyl,
represents (C1-C8)-alkyl which is optionally interrupted by an oxygen or sulphur atom or by a radial NR6.
represents a 4 to 8-membered saturated heterocycle which is attached to the imidazole ring via a nitrogen atom and which optionally contains a further oxygen or sulphur atom, or
represents a 4- to 8-membered saturated heterocycle which contains a radical of the formula NR7 and optionally additionally one nitrogen, oxygen or sulphur atom,
where (C3-C8)cycloalkyl, (C1-C8)-alkyl which is optionally interrupted by one oxygen or sulphur atom, the 4- to 8-membered saturated heterocycle which is attached to the imidazole ring via a nitrogen atom and which optionally contains one further oxygen or sulphur atom and optionally (C1-C8)-alkyl which is interrupted by a radical NR6 and optionally the 4 to 8-membered saturated heterocycle which contains a radical of the formula NR7 and optionally additionally one nitrogen, oxygen or sulphur atom are substituted by one to three hydroxyl groups and/or by a radical of the formula xe2x80x94NR8R9 
in which
R6 and R7 are identical or different and each represents hydrogen, (C1-C6)-alkyl, hydroxy-(C1-C6)-alkyl or (C3-C7)-cycloalkyl.
R8 and R9 are identical or different and each represents hydrogen, (C1-C6)-alkyl or (C3-C7)-cycloalkyl,
or
R8 and R9 together with the nitrogen atom form a 4- to 8-membered saturated heterocycle which may optionally additionally contain one oxygen or sulphur atom or a radical of the formula NR10 
in which
R10 represents hydrogen, (C1-C6)alkyl or (C3-C7)-cycloalkyl and
R3 represents a phenyl, naphthyl, pyrimidinyl, pyridyl, furyl or thienyl ring, where the rings are optionally mono- or polysubstituted by radicals selected from the group consisting of halogen, hydroxyl, carboxyl, cyano, nitro, trifluoromethyl, trifluoromethoxy, (C1-C6)-alkyl, (C1-C6)-alkoxy or (C1-C6)-alkoxycarbonyl,
and their salts.
Physiologically acceptable salts of the compounds according to the invention can be salts of the substances according to the invention with mineral acids, carboxylic acids or sulphonic acids. Particular preference is given, for example, to salts with hydrochloric acid, hydrobromic acid, sulphuric acid, phosphoric acid, methanesulphonic acid, ethanesulphonic acid, toluenesulphonic acid, benzenesulphonic acid, naphthalenedisulphonic acid, acetic acid, propionic acid, lactic acid, tartaric acid, citric acid, fumaric acid, maleic acid or benzoic acid.
The compounds of the general formula (I) according to the invention can occur in different stereoisomeric forms which are either like image and mirror image (enantiomers), or which are not like image and mirror image (diastereomers). The invention relates both to the enantiomers and to the diastereomers and their respective mixtures. The racemic forms, like the diastereomers, can be separated in a known manner into the stereoisomerically uniform components.
Furthermore, certain compounds can be present in tautomeric forms. This is known to the person skilled in the art, and such compounds are likewise included in the scope of the invention.
(C1-C8)-Alkyl, C1-C6)-alkyl etc., represent a straight-chain or branched alkyl radical having 1 to 8 or 1 to 6 carbon atoms. Examples which may be mentioned are: methyl, ethyl, n-propyl, isopropyl, tert-butyl, n-pentyl and n-hexyl. Preference is given to a straight-chain or branched alkyl radical having 1 to 4 carbon atoms (C1-C4). Particular preference is given to a straight-chain or branched alkyl radical having 1 to 3 carbon atoms (C1-C3).
(C1-C8)-Alkyl, (C1-C6)-alkyl etc., which is interrupted by one oxygen or sulphur atom and which is substituted by one to three hydroxyl groups and/or by a radical of the formula xe2x80x94NR8R9 represents, for example, 1,3-dihydroxy-prop-2-oxy-methyl, 2-hydroxy-ethoxy-methyl, 2-hydroxy-prop-1-oxy-methyl, 3-hydroxy-prop-1-oxy-methyl, morpholin-4-yl-methyl, piperidin-1-yl-methyl, 2-amino-ethyl, 2-dimethylamino-ethyl or diethylamino-methyl.
(C1-C8)-Alkyl, (C1-C6)-alkyl etc., which is interrupted by a radical N6 and which is optionally substituted by one to three hydroxyl groups and/or by a radical of the formula xe2x80x94NR8R9 represents, for example, N-(2-hydroxy-ethyl)-aminomethyl, N-(2-hydroxy-ethyl)-N-methyl-aminomethyl or N,N-bis-(2-hydroxy-ethyl)-aminomethyl.
Hydroxy-(C1-C6)-alkyl or hydroxy-(C1-C4)-alkyl represents a straight-chain or branched alkyl radical having 1 to 6 or 1 to 4 carbon atoms. The examples which may be mentioned are: hydroxymethyl, 2-hydroxy-ethyl, 2-hydroxy-prop-1-yl, 3-hydroxy-prop-1-yl, 3-hydroxy-prop-2-yl, 2-hydroxy-but-1-yl, 5-hydroxy-pent-1-yl and 6-hydroxy-hex-1-yl. Preference is given to 2-hydroxy-ethyl.
(C1-C6)-Alkoxy represents a straight-chain or branched alkoxy radical having 1 to 6 carbon atoms. Examples which may be mentioned are: methoxy, ethoxy, n-propoxy, isopropoxy, tert-butoxy, n-pentoxy and n-hexoxy. Preference is given to a straight-chain or branched alkoxy radical having 1 to 4 carbon atoms (C1-C4). Particular preference is given to a straight-chain or branched alkoxy radical having 1 to 3 carbon atoms (C1-C3).
(C1-C6)-Alkoxycarbonyl represents a straight-chain or branched alkoxycarbonyl radical having 1 to 6 carbon atoms. Examples which may be mentioned are: methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl and tert-butoxycarbonyl. Preference is given to a straight-chain or branched alkoxycarbonyl radical having 1 to 4 carbon atoms (C1-C4). Particular preference is given to a straight-chain or branched alkoxycarbonyl radical having 1 to 3 carbon atoms (C1-C3).
(C3-C8)-Cycloalkyl, (C3-C7)-cycloalkyl etc., represents, in the context of the invention, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl. Cyclopropyl, cyclopentyl and cyclohexyl may be mentioned as being preferred.
Halogen in the context of the invention generally represents fluorine, chlorine, bromine and iodine. Preference is given to fluorine, chlorine and bromine. Particular preference is given to fluorine and chlorine.
In the context of the invention, a 4- to 8-membered (preferably 5- to 7-membered) saturated heterocycle which is attached via a nitrogen atom and which optionally contains one further oxygen or sulphur atom represents, for example, pyrrolidin-1-yl, piperidin-1-yl, morpholin-4-yl, thiomorpholin-4-yl or 1H-hexahydroazepin-1-yl.
In the context of the invention, a 4- to 8-membered (preferably 5- to 7-membered) saturated heterocycle which contains a radical of the formula NR7 and optionally additionally one nitrogen, oxygen or sulphur atom represents, for example, pyrrolidin-2-yl, 1-methylpyrrolidin-2-yl, pyrrolidin-3-yl, pyrazolidin-1-yl, piperidin-2-yl, 1-isopropyl-piperidin-3-yl, morpholin-2-yl, 4-cyclohexyl-piperazin-1-yl, thiomorpholin-3-yl, 1-ethyl-1H-hexahydroazepin-3-yl or 4-methyl-1H-hexahydro-1,4-diazepin-1-yl. This heterocycle can be attached to the imidazole ring via a ring carbon atom or a ring nitrogen atom.
Preference is given to compounds of the general formula (I) which have the absolute configuration given in the general formula (Ixe2x80x2) 
The compounds according to the invention can be present in four different relative configurations (A) to (D): 
Preference is given to the configuration (D).
Preference is likewise given to compounds of the general formula (I) in which R1 represents a radical of the formula COxe2x80x94R4R5 where R4 and R5 are each as defined above. Moreover, preference is given to those compounds of the general formula (I) in which R2 contains a basic nitrogen atom.
Basic nitrogen atom is to be understood as meaning a nitrogen atom which, after protonation of the compound under aqueous standard conditions, has a pKa of more than 6.
Particular preference is given to compounds of the general formula (I) according to the invention
where
A, D, E and G each represent the CH group,
or one of the radicals A, D, E and G represents a nitrogen atom and the others each represent the CH group,
L1and L2 are identical or different and independently of one another each represents one or more radicals selected from the group consisting of hydrogen, fluorine, chlorine, cyano, trifluoromethyl or trifluoromethoxy,
R1represents the xe2x80x94CH2xe2x80x94OH group, or
represents a radical of the formula xe2x80x94COxe2x80x94NR4R5 
in which
R4 and R5 are identical or different and each represents hydrogen or (C1-C3)-alkyl.
R2 represents (C3-C7)-cycloalkyl,
represents (C1-C6)-alkyl which is optionally interrupted by an oxygen or sulphur atom or by a radical NR6,
represents a 5- to 7-membered saturated heterocycle which is attached to the imidazole ring via a nitrogen atom and which optionally contains a further oxygen or sulphur atom, or
represents a 5- to 7-membered saturated heterocycle which contains a radical of the formula NR7 and optionally additionally one nitrogen, oxygen or sulphur atom,
where (C3-C7)-cycloalkyl, (C1-C6)-alkyl which is optionally interrupted by one oxygen or sulphur atom, the 5- to 7-membered saturated heterocycle which is attached to the imidazole ring via a nitrogen atom and which optionally contains one further oxygen or sulphur atom and optionally (C1-C6)-alkyl which is interrupted by a radical NR6 and optionally the 5- to 7-membered saturated heterocycle which contains a radical of the formula NR7 and optionally additionally one nitrogen, oxygen or sulphur atom are substituted by a hydroxyl group and/or by a radical of the formula xe2x80x94NR8R9 
in which
R6 and R7 are identical or different and each represents hydrogen, (C1-C4)-alkyl hydroxy-(C1-C4)-alkyl or (C3-C6)-cycloalkyl.
R8 and R9 are identical or different and each represents hydrogen, (C1C4)-alkyl or (C3-C6)-cycloalkyl,
or
R8 and R9 together with the nitrogen atom form a 5- to 7-membered saturated heterocycle which may optionally additionally contain one oxygen or sulphur atom or a radical of the formula NR10 
in which
R10 represents hydrogen, (C1-C4)-alkyl or (C3-C6)-cycloalkyl
and
R3 represents a phenyl, pyridyl or thienyl ring which is optionally mono- or polysubstituted by radicals selected from the group consisting of fluorine, chlorine, cyano, trifluoromethyl or trifluoromethoxy,
and their salts.
Very particular preference is given to compounds of the general formula (I)
where
A, D and E each represent a CH group,
G represents a nitrogen atom or represents a CH group,
L1and L2 each represent hydrogen.
R1 represents a radical of the formula xe2x80x94COxe2x80x94NR4R5,
in which
R4 and R5 each represent hydrogen,
R2 represents (C1-C4)-alkyl which is optionally interrupted by one oxygen atom, or
represents a 4-R7-piperazin-1-yl radical
where (C1-C4)-alkyl which is optionally interrupted by one oxygen atom is substituted by a hydroxyl group or by a radical of the formula xe2x80x94NR8R9 
in which
R7 represents hydrogen, (C1-C4)-alkyl or (C3-C6)-cycloalkyl,
R8 and R9 arm identical or different and each represents hydrogen, (C1-C4)-alkyl or (C3-C6)-cycloalkyl,
or
R8 and R9 together with the nitrogen atom form a morpholine radical,
and
R3 represents a phenyl radical,
and their salts.
Moreover, processes for preparing the compounds of the general formula (I) have been found which are characterized in that
[A] compounds of the general formula (II) 
in which
L2 is as defined above,
T represents (C1-C4)-alkyl, preferably methyl or tert-butyl,
and
V represents a suitable leaving group, such as, for example, halogen, mesylate or tosylate, preferably bromine,
is initially converted by reaction with compounds of the general formula (III) 
in which
A, D, E, G and L1 are each as defined in claim 1
and
R11 has the meaning of R2 given in claim 1, where amino and hydroxyl functions are optionally blocked by suitable amino or hydroxyl protective groups,
in inert solvents, depending on the definition of R11 optionally in the presence of a base, into the compounds of the general formula (IV) 
in which
R11, A, D, E, G, L1, L2 and T are each as defined above,
which are converted in a subsequent step using acids or bases into the corresponding carboxylic acids of the general formula (V) 
in which
R11, A, D, E, G, L1 and L2 are each as defined above,
which are subsequently, following activation, reacted by known methods with compounds of the general formula (VI) 
in which
R1and R3 are each as defined above
in inert solvents,
and, if R11 carries one of the abovementioned protective groups, these are optionally removed by customary methods either in the hydrolysis to the acids (IV)xe2x86x92(V) or after the reaction with the compounds of the general formula (VI),
or
[B] if R2 represents a saturated heterocycle which is attached directly via a nitrogen atom to the imidazole ring,
the abovementioned compounds of the general formula (II) are initially converted with compounds of the general formula (IIIa) 
in which
A, D, E, G and L1 are each as defined above
Y represents halogen or mesyl, preferably chlorine, bromine or mesyl, in inert solvents into the corresponding compounds of the formula (VII) 
in which
Y, A, D, E, G, L1, L2 and T are each as defined above, which are reacted in a subsequent step with compounds of the general formula (VIII)
HNR12R13 (VIII)
in which
R12 and R13 together with the nitrogen atom form a heterocycle according to the definition of R2 
to give compounds of the general formula (IX) 
in which
A, D, E, G, L1, L2, R12, R13 and T are each as defined above,
which are, in the subsequent steps, converted as described under [A] by hydrolysis into the corresponding carboxylic acids of the general formula (X) 
in which
A, D, E, G, L1, L2, R12 and R13 are each as defined above,
and these compounds are subsequently, following activation, reacted with the compounds of the general formula (VI) according to known methods for preparing amides from carboxylic acids and amines and, if appropriate, converted into the corresponding salts by reaction with an acid.
The processes according to the invention can be illustrated in an exemplary manner by the formula schemes below: 
Suitable amino protective groups in the context of the invention are the customary amino protective groups used in peptide chemistry.
These preferably include: benzyloxycarbonyl, 3,4-dimethoxybenzyloxycarbonyl, 3,5-dimethoxybenzyloxycarbonyl, 2,4-dimethoxybenzyloxycarbonyl, 4-methoxy-benzyloxycarbonyl, 4-nitrobenzyloxycarbonyl, 2-nitrobenzyloxycarbonyl, 2-nitro-4,5-dimethoxybenzyloxycarbonyl, methoxycarbonyl, ethoxycarbonyl, propoxy-carbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, tert-butoxy-carbonyl, allyloxycarbonyl, vinyloxycarbonyl, 2-nitrobenzyloxycarbonyl, 3,4,5-trimethoxybenzyloxycarbonyl, cyclohexoxycarbonyl, 1,1-dimethylethoxycarbonyl, adamantylcarbonyl, phthaloyl, 2,2,2-trichloroethoxycarbonyl, 2,2,2-trichloro-tert-butoxycarbonyl, menthyloxycarbonyl, phenoxycarbonyl, 4-nitrophenoxycarbonyl, fluorenyl-9-methoxycarbonyl, formyl, acetyl, propionyl, pivaloyl, 2-chloroacetyl, 2-bromoacetyl, 2,2,2-trifluoroacetyl, 2,2,2-trichloroacetyl, benzoyl, 4-chlorobenzoyl, 4-bromobenzoyl, 4-nitrobenzoyl, phthalimido, isovaleroyl or benzyloxymethylene, 4-nitrobenzyl, 2,4-dinitrobenzyl or 4-nitrophenyl. A preferred protective group for primary amines is phthalimide. Preferred protective groups for secondary amines are benzyloxycarbonyl and tert-butoxycarbonyl.
The amino protective groups can be removed in a manner known per se, for example under the hydrogenolytic, acidic or basic conditions, preferably using acids, such as, for example, hydrochloric acid or trifluoroacetic acid, in inert solvents, such as ether, dioxane and methylene chloride,
A suitable hydroxy protective group in the context of the definition given above is generally a protective group from the series: trimethylsilyl, triethylsilyl, triisopropylsilyl, tert-butyl-dimethylsilyl, dimethylthexylsilyl, tert-butyl-diphenylsilyl, trimethylsilylethoxycarbonyl, benzyl, triphenylmethyl (trityl), monomethoxytrityl (MMTr), dimethyloxytrityl (DMTr), benzyloxycarbonyl, 2-nitrobenzyl, 4nitro-benzyl, 2-nitrobenzyloxycarbonyl, 4-nitrobenzyloxycarbonyl, tert-butyloxycarbonyl, 4-methoxybenzyl, 4-methoxybenzyloxycarbonyl, formyl, acetyl, trichloroacetyl, 2,2,2-trichloroethoxycarbonyl, 2,4dimethoxybenzyl, 2,4dimethoxybenzyl-oxycarbonyl, methoxymethyl, methylthiomethyl, methoxyethoxymethyl, [2-trimethylsilyl)ethoxy]-methyl, 2-(methylthiomethoxy)ethoxycarbonyl, tetra-hydropyranyl, benzoyl, N-succinimide, 4methylbenzoyl, 4-nitrobenzoyl, 4-fluorobenzoyl, 4-chlorobenzoyl or 4-methoxybenzoyl. Preference is given to tert-butyldimethylsilyl.
The hydroxy protective group can be removed in a manner known per se, for example using acid or base, or by addition of tetrabutyl ammoniumfluoride; or is carried out during the hydrolysis of the carboxylic acid.
Suitable solvents for the processes are customary organic solvents which do not change under the reaction conditions. These include ethers, such as diethyl ether, dioxane, terahydrofuran, glycol dimethyl ether, or hydrocarbons, such as benzene, toluene, xylene, hexane, cyclohexane or mineral oil fractions, or halogenated hydrocarbons, such as dichloromethane, trichloromethane, tetrachloromethane, dichloroethylene, trichloroethylene or chlorobenzene, or ethyl acetate, pyridine, dimethyl sulphoxide, dimethylformamide, hexamethylphosphoric triamide, acetonitrile, acetone or nitromethane. It is also possible to use mixtures of the solvents mentioned. For the process [A] (II)+(III)xe2x86x92(IV), preference is given to diethyl ether, tetrahydrofuran and dimethylformamide. Particular preference is given to dimethylformamide.
Suitable for use as bases in the process according to the invention are, in general, inorganic or organic bases. These preferably include alkali hydroxides, such as, for example, sodium hydroxide or potassium hydroxide, alkaline earth metal hydroxides, such as, for examples barium hydroxide, alkali metal carbonates, such as sodium carbonate, potassium carbonate or caesium carbonate, alkaline earth metal carbonates, such as calcium carbonate, or alkali metal or alkaline earth metal alkoxides, such as sodium methoxide or potassium methoxide, sodium ethoxide or potassium ethoxide or potassium tert-butoxide, or organic amines (trialkyl(C1-c6)amines), such as triethylamine, or heterocycles, such as 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), pyridine, diaminopyridine, methylpiperidine or morpholine. It is also possible to use, as bases, alkali metals, such as sodium, or their hydrides, such as sodium hydride. Preference is given to sodium hydride, potassium carbonate, caesium carbonate, triethylamine, trimethylamine, pyridine, potassium tert-butoxide, DBU or DABCO. Very particularly preferred for the step [A](II)+(III)xe2x86x92(IV) is the use of sodium hydride.
In general, the bases are employed in an amount of from 0.05 mol to 10 mol, preferably from 1 mol to 2 mol, based on 1 mol of the compound of the formula (II).
The process (II)+(III)xe2x86x92(IV) according to the invention is generally carried out in a temperature range from xe2x88x9220xc2x0 C. to +60xc2x0 C., preferably from 0xc2x0 C. to +60xc2x0 C.
The process (II)+(III)xe2x86x92(IV) according to the invention is generally carried out under atmospheric pressure. However, it is also possible to carry out the process under elevated pressure or under reduced pressure (for example in a range from 0.5 to 5 bar.
The hydrolysis of the carboxylic esters is carried out by customary methods by treating the esters in inert solvents with customary bases, the salts which are formed initially being converted by treatment with acid into the free carboxylic acids, or, in the case of the t-butyl esters, with acid.
Suitable bases for the hydrolysis are the customary inorganic bases. These preferably include alkali metal hydroxides or alkaline earth metal hydroxides, such as, for example, sodium hydroxide, lithium hydroxide, potassium hydroxide or barium hydroxide, or alkali metal carbonates, such as sodium carbonate or potassium carbonate or sodium bicarbonate. Particular preference is given to using sodium hydroxide or lithium hydroxide.
Suitable acids are, in general, trifluoroacetic acid, sulphuric acid, hydrogen chloride, hydrogen bromide and acetic acid, or mixtures thereof, if appropriate with addition of water. Preference is given to hydrogen chloride or trifluoroacetic acid in the case of the tert-butyl esters and to hydrochloric acid in the case of the methyl esters.
Solvents which are suitable for the hydrolysis are water or organic solvents customarily used for hydrolysis. These preferably include alcohols, such as methanol, ethanol, propanol, isopropanol or butanol, or ethers, such as tetrahydrofuran or dioxane, dimethylformamide, dichloromethane or dimethyl sulphoxide. It is also possible to use mixtures of the solvents mentioned. Preference is given to water/tetrahydrofuran and, in the case or the reaction with trifluoroacetic acid, dichloromethane and, in the case of hydrogen chloride, tetrahydrofuran, diethyl ether or water.
The hydrolysis is generally carried out in a temperature range from 0xc2x0 C. to +100xc2x0 C.
In general, the hydrolysis is carried out at atmospheric pressure. However, it is also possible to operate under reduced pressure or under elevated pressure (for example from 0.5 to 5 bar).
When carrying out the hydrolyses, the base or the acid is generally employed in an amount of from 1 to 100 mol, preferably from 1.5 to 40 mol, based on 1 mol of the ester.
The carboxylic acids (V) are usually activated by being converted into the corresponding acyl halides, preferably acyl chlorides, or pre-activation with a customary condensing agent, which cam take place in situ or by isolating the activated carboxylic acid derivative. The acyl halides can be prepared by customary methods. The use of oxalyl chloride or thionyl chloride may be mentioned as an example.
Preferred auxiliaries used for the amide formations are condensing agents. Preference is given here to using the customary condensing agents, such as carbodiimides, for example N,Nxe2x80x2-diethyl-, N,Nxe2x80x2-dipropyl-, N,Nxe2x80x2-diisopropyl-, N,Nxe2x80x2-dicyclohexyl-carbodiimide, N-(3-dimethylaminoisopropyl)-Nxe2x80x2-ethylcarbodiimide hydrochloride (EDC) or carbonyl compounds, such as carbonyldiimidazole, or 1,2-oxazolium compounds, such as 2-ethyl-5-phenyl-1,2-oxazolium-3-sulphate or 2-tert-butyl-5-methyl-isoxazolium perchlorate, or acylamino compounds, such as 2ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline, or propanephosphonic acid anhydride, or isobutyl chloroformate, or bis-(2-oxo-3-oxazolidinyl)-phosphoryl chloride or benzotriazolyloxy-tri(dimethylamino)phosphonium hexafluorophosphate and, as bases, alkali metal carbonates, for example sodium carbonate or bicarbonate and potassium carbonate or bicarbonate, or organic bases, such as trialkylamines, for example triethylamine, N-ethylmorpholine, N-methylpiperidine or diisopropyl-ethylamine. Particular preference is given to the combination of EDC. N-methylmorpholine and 1-hydroxybenzotriazole. Preferred solvents for the amide formation are dichloromethane and DMF.
The compounds of the general formulae (II), (IIIa), (VI) and (VII) are known or can be prepared by customary methods (cf. EP-A-0 725 061, EP-A-0 725 064).
Most or the compounds or the general formula (III) are novel, and they can be prepared, in the case that R11 does not represent a heterocycle which is attached directly via N, by reacting compounds of the general formula (XI) 
in which
A, D, E, G and L1are each as defined above
with compounds of the general formula (XII)
R11xe2x80x94CO2Hxe2x80x83xe2x80x83(XII)
in which
R11 is as defined above
with removal of the water of reaction, if appropriate in the presence of an acid, preferably PPA, HCl and p-TsOH (cf. also J. Org. Chem. 1941. 6, 25 ff. and Bull. Soc. Chem. Fr. 1991, 128, 255-259)
and, in the case that R11 represents one of the radicals listed above under R2 which may optionally also carry a protective group, by converting compounds of the general formula (XI) initially by reaction with compounds of the general formula (XIII)
HOxe2x80x94R14xe2x80x94CO2Hxe2x80x83xe2x80x83(XIII)
in which
R14 represents (C1-C8)alkanediyl
into compounds of the general formula (XIV) 
in which
A, B, D, G, R14 and L1 are each as defined above
in insert solvents,
subsequently substituting the hydroxyl group by halogen, mesylate or tosylate, thus producing the compounds of the general formula (XV) 
in which
R14, A, D, E, G and L1 are each as defined above
and
Z represents halogen, mesylate or tosylate,
and reacting these with amines of the general formula (XVI)
R8R9NHxe2x80x83xe2x80x83(XVI)
in which
R8 and R9 are each as defined above
(cf. also J. Am. Chem. Soc. 1948, 70, 3406; J. Heterocycl. Chem. 1969, 759-60).
Solvents which are suitable for the process are customary organic solvents which do not change under the reaction conditions. These preferably include ethers, such as diethyl ether, dioxane, tetrahydrofuran, glycol dimethyl ether, or hydrocarbons, such as benzene, toluene, xylene, hexane, cyclohexane or mineral oil fractions, or halogenated hydrocarbons, such as dichloromethane, trichloromethane, carbon tetrachloride, dichloroethylene, trichloroethylene or chlorobenzene, or ethyl acetate, triethylamine, pyridine, dimethyl sulphoxide, dimethylformamide, hexamethylphosphoric triamide, acetonitrile, acetone or nitromethane. It is also possible to use mixtures of the solvents mentioned. Preference is given to dichloromethane, tetrahydrofuran and dimethylformamide.
Bases suitable for use in the process according to the invention arc, in general, inorganic or organic bases. These preferably include alkali metal hydroxides, such as, for example, sodium hydroxide or potassium hydroxide, alkaline earth metal hydroxides, such as, for example, barium hydroxide, alkali metal carbonates, such as a; sodium carbonate, potassium carbonate or caesium carbonate, alkaline earth metal w carbonates, such as calcium carbonate, or alkali metal or alkaline earth metal alkoxides, such as sodium methoxide or potassium methoxide, sodium ethoxide or potassium ethoxide or potassium tert-butoxide, or organic amines (trialkyl(C1-C6)amines) such as triethylamine, or heterocycles such as 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), pyridine, diaminopyridine, methylpiperidine or morpholine. It is also possible to use, as bases, alkali metals, such as sodium, or their hydrides, such as sodium hydride. Preference is given to sodium hydride, potassium carbonate, triethylamine, trimethylamine, pyridine, potassium tert-butoxide, DBU or DABCO.
In general, the bases are employed in an amount of from 0.05 mol to 10 mol, preferably from 1 mol to 2 mol, based on 1 mol of the compound of the formula (XV).
The process according to the invention is generally carried out in a temperature range of from xe2x88x9250xc2x0 C. to +100xc2x0 C., preferably from xe2x88x9230xc2x0 C. to +60xc2x0 C.
The process according to the invention is generally carried out under atmospheric pressure. However, it is also possible to carry out the process under elevated pressure or under reduced pressure (for example in a range from 0.5 to 5 bar).
The compounds of the general formulae (XI), (XII), (XIII) and (XVI) are known per se or can be prepared by customary methods.
Some of the compounds of the general formulae (XIV) and (XV) are novel, and they can be prepared, for example, as described above.
The compounds of the general formulae (IV), (V), (VII), (IX) and (X) and their salts are novel and can be prepared as described above.
Surprisingly, the compounds of the general formula (I) according to the invention and their analogues have an unforeseeable useful pharmacological activity spectrum, combined with an improved solubility in water.
It has been found that the compounds according to the invention inhibit adenosine uptake.
They can be used orally or intravenously for the prophylaxis and treatment of cerebral ischaemia, stroke, reperfusion damage, brain trauma, oedema, spasms, epilepsy, respiratory arrest, cardiac arrest, Reye""s syndrome, cerebral thrombosis, emboli, tumours, haemorrhages, encephalomyelitis, hydroencephalitis, spinal injuries, postoperative brain damage, injuries to the retina or the optical nerve after glaucoma, ischaemia, hypoxia, oedema or trauma and in the treatment of schizophrenia, sleep disturbances and pain.
Owing to their improved solubility in water, the compounds according to the invention are particularly suitable for intravenous administration.
1. Determination of the Solubility
To determine the solubility, a precipitation method was used:
10 mg of the test substance are completely dissolved in 50 xcexcl of DMSO (stock solution). 20 xcexcl of this solution are added to 2000 xcexcl of physiological saline. This solution, in turn, is shaken at 25xc2x0 C. in a Thermomixer Comfort (from Eppendorf) at 1400 rpm for 24 hours for equilibration.
The precipitated fractions of the test substance are centrifuged off using a Biofuge 15 from Heraeus at 14,000 rpm for 5 min. 1300 xcexcl of the supernatant are once more centrifuged using a Microfuge from Beckmann at 45,000 rpm=125,000 g.
10 xcexcl of this centrifigation supernatant are then diluted with 1000 xcexcl of DMSO, and this solution is measured by HPLC (Hewlett Packard 1090, method, gradient from 100% PBS buffer pH=4 to 10% buffer/90% acetonitrile over a period of 15 min, column: RPI8; PBS buffer pH=4 is a physiological saline solution adjusted to pH=4 using phosphate buffer).
Using a calibration curve, the measured peak area of the HPLC measurement is converted into substance concentration. For the calibration curve, 20 xcexcl of the stock solution are diluted successively with DMSO such that 5 concentrations of 2.5 mg/l to 2000 mg/l result. These solutions are likewise measured by HPLC (see method above), and the peak areas are plotted as a function of the concentrations.
The solubility, determined by this method, of Examples 3 and 5 is 176 and 16 mg/l, respectively.
2. Binding of the Compounds According to the Invention to an Adenosine Transport Protein From Calf Cortex
The ability of substances to influence the adenosine uptake system is investigated firstly by determining the binding affinity of selected substances to an adenosine transport protein of the CNS and secondly by determining the inhibiting effect of the substances on functional adenosine uptake.
For the binding test, a membrane preparation of cerebral calf cortex is used, which expresses the relevant adenosine transporter. The binding affinity (Ki value) is determined by measuring the displacement of a specific radio-labelled ligand [nitrobenzylthioinosine (NBTI)] from the binding site in question by test substances. The binding site is the binding site on the transport protein which is relevant for the actual transport process. Thus, binding of test substances in this experiment results in a quantifiable release of bound radioactive NBTI which makes determination of the Ki value possible. (J. Neurochemistry 1982,39, 184-191).
Examples 3 and 5 inhibit NBTI-binding, in each case with Ki=2 nM.
3. Inhibition of Adenosine Uptake in Calf Cortex Synaptosomes by Compounds According to the Invention
For the functional adenosine uptake test, a synaptosome preparation from cerebral calf cortex is used which expresses the adenosine transporter in question. Synaptosomes are cell-free, functionally active vesicles which are obtained from cortex tissue using sheer forces and which still have the properties of an intact synaptic knob. The inhibitory activity (IC50 value) is determined by measuring the inhibition of the uptake of the specific radio-labelled xe2x80x9csubstratexe2x80x9d adenosine into the synaptosomes (J. Neurochemistry 1990, 55, 541-550).
Examples 3 and 5 inhibit adenosine uptake into synaptosomes with IC50=8 nM and 14 nM, respectively.
The neuroprotective activity of the compounds according to the invention was determined in the animal model of transient occlusion of the middle cerebral artery (tMCA-O) and the subdural haematoma (SDH).
4. tMCA-O
This rodent model (rat) imitates the pathophysiology and cerebral pathology of stroke or circulatory arrest (embolization, thrombosis, vaso spasm, cardiac arrest, rapidly and dramatically reduced blood pressure, high blood loss, etc.) with subsequent recirculation in man (modified according to: J. Cereb. Blood Flow Metab. 1997, 17, 1066-1073).
Under general anaesthesia (inhalation anaesthesia with isoflurane), the hairs in the lower anterior neck region are shaved off, in the dorsal position, the head is fixed, the skin is disinfected and the neck area is opened in the middle along the trachea. The right lateral neck muscles are severed bluntly and, together with the skin, pulled to the side (retractors) so that the common carotid artery is clearly visible. The common carotid artery is exposed towards the head up to the point where it branches into the internal carotid artery and the external carotid artery. Using surgical suture material, the common carotid artery (near the thorax) and the external carotid artery are tied off. Using a microclamp; the internal carotid artery is closed temporarily. The common carotid artery is opened, and a nylon monofilament with a rounded tip and a silicone cylinder of a length of 1 cm are passed through the common carotid artery and, after opening of the microclamp; further through the internal carotid artery, to close the exit of the middle cerebral artery. Using two temporary suture loops, the filament is fixed in the internal carotid artery. Alter one hour, the filament is pulled out, and the internal carotid artery and the common carotid artery are tied off above the opening. Blood is supplied via the contralateral muscular system.
Substance administration is begun directly with the start of reperfusion. The operation wound is surgically looked after. During the operation and the administration of the substance (infusion), the body temperature is kept constant using a heating plate.
After 2 days of post-operative survival, the volume of the cerebral infarct is determined with the aid of a computer-supported image analysis system using preproduced series of histological brain sections. The size of the infarct is evaluated differentially by cortex, striatum, hippocampus and other brain areas.
At a dose of 0.001 mg/(kgxc3x97h) (i.v. infusion), Examples 3 and 5 reduce the infarct volume by 81 and 91%, respectively, in comparison to control animals.
5. Subdural Haematoma in Rats (SDH)
This rodent model (rat) imitates pathophysiology and cerebral pathology of the blunt skull-brain trauma with subdural hemorrhage and development of a subdural haematoma in man. (Neurosurgery 190, 27,433-439).
Under anaesthesia, the animals are unilaterally injected subdurally with their own blood. Under the haematoma, an infarct forms. The substance is administered according to different schedules and via different administration routes (i.v., i.p.). The size of the infarct is determined as described in the model of the transient focal ischaemia in rats (tMCA-O).
At a dose of 0.001 mg/(kgxc3x97h) (i.v. infusion), Examples 3 and 4 reduce the infarct volume by 30 and 45%, respectively, in comparison to control animals.
The novel active compounds can be converted in a known manner into the customary formulations, such as tablets, coated tablets, pills, granules, aerosols, syrups, emulsions, suspensions and solutions, using inert, nontoxic, pharmaceutically suitable carriers or solvents. In this case the therapeutically active compound should in each case be present in a concentration of about 0.0001 to 900% by weight, preferably 0.0001 to 1.0% by weight, of the total mixture, i.e. in amounts which are sufficient in order to achieve the dosage range indicated.
The formulations are prepared, for example, by extending the active compounds with solvents and/or excipients, if appropriate using emulsifiers and/or dispersants, where, for example, if the diluent used is water, organic solvents can optionally be used as auxiliary solvents.
Administration is carried out in a customary manner, preferably orally, transdermally or parenterally, in particular perlingually or intravenously.
In general it has proven advantageous in the case of intravenous administration to administer amounts of approximately 0.00001 to 10 mg/kg, preferably approximately 0.0001 to 1 mg/kg, of body weight to achieve effective results.
In spite of this, if appropriate, it may be necessary to depart from the amounts mentioned, namely depending on the body weight or the type of administration route, on the individual response to the medicament, the manner of its formulation and the time or interval at which administration takes place. Thus, in some cases it may be adequate to manage with less than the abovementioned minimum amount, while in other cases the upper limits mentioned must be exceeded. In the case of the administration of relatively large amounts, it may be advisable to divide these into several individual doses over the course of the day.